In the graphics industry, so called test charts must often be densitometrically or calorimetrically measured, for which hand scanners are used. Such test charts include a large number of special measurement fields on a single sheet onto which a scanning head of the hand scanner is positioned for the measurement. Especially for test charts with a large number of measurement fields (e.g., (several hundred), an automatic positioning of the scanner would significantly reduce the amount of time and effort required for positioning the scanning head.
Different solutions for this automatic positioning are already on the market. One of the best known solutions includes an X-Y Table which can receive a hand scanner and drive the hand scanner across the measurement original according to the principle of an X-Y slide table in two orthogonal coordinate directions under the control of a computer. The mechanics required to drive the hand scanner, such as motors and guides, require a relatively large amount of space and are therefore normally positioned under the table for the original. However, with this arrangement, a transmission measurement is then not possible. When transmission measurements are required, the mechanics for driving the hand scanner need to be positioned beside the support for the original, whereby the overall measurement arrangement becomes relatively large even for small sized originals including for example A4 size (210 mm×297 mm).